This invention relates to a method and an apparatus for generating a musical tone signal in which a plurality of partial tone components are formed according to the tone pitch of a musical tone to be produced and these components are synthesized at suitable levels to produce a desired musical tone signal and more particularly a method and an apparatus for generating a musical tone signal capable of producing a musical tone signal containing a plurality of partial tone components with a simple construction.
A method of generating a musical tone signal by utilizing digital technique is disclosed in Japanese preliminary Publication of Patent No. 12172/1978 (corresponding to U.S. Pat. No. 4,282,790 assigned to the same assignee as the present application) which reaches a partial tone synthesizing system.
In such a musical tone generating system of the partial tone synthesizing type there are provided the number of calculating channels equal to the number of the partial tone components to be synthesized, and the calculating channels are used to calculate the partial tone components of preassigned orders and these calculated partial tone components are synthesized at suitable levels to generate a desired musical tone.
The term "calculating channel" used herein means a time slot for calculating each partial tone component on the time division basis where a single arithmetical operation circuit is used for calculation, or respective arithmetical operation circuits which are of the same number as the number of partial tone components where the arithmetical operation circuit are used in parallel for calculating the partial tone components.
According to the prior art musical tone signal generating system described above, since each calculating channel calculates only one predetermined partial tone component it is necessary to prepare the same number of calculating channels as that of the partial tone components to be synthesized, so that where a musical tone signal including many partial tone components is to be produced, the number of calculating channels increases greatly thus making the musical tone signal generating apparatus bulky.